Heap-002-shift-up

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本文介绍了一个使用C++实现的最大堆数据结构，包括插入元素和打印堆的功能。通过随机数测试，展示了最大堆的构建过程。

main.cpp

#include <iostream>
#include <algorithm>
#include <string>
#include <ctime>
#include <cmath>
#include <cassert>

using namespace std;


template<typename Item>
class MaxHeap{

private:
    Item *data;
    int count;
    int capacity;

    void shiftUp(int k){
        while( k > 1 && data[k/2] < data[k] ){
            swap( data[k/2], data[k] );
            k /= 2;
        }
    }

public:

    MaxHeap(int capacity){
        data = new Item[capacity+1];
        count = 0;
        this->capacity = capacity;
    }

    ~MaxHeap(){
        delete[] data;
    }

    int size(){
        return count;
    }

    bool isEmpty(){
        return count == 0;
    }

    void insert(Item item){
        assert( count + 1 <= capacity );
        data[count+1] = item;
        count ++;
        shiftUp(count);
    }


public:
    void testPrint(){

        if( size() >= 100 ){
            cout<<"Fancy print can only work for less than 100 int";
            return;
        }

        if( typeid(Item) != typeid(int) ){
            cout <<"Fancy print can only work for int item";
            return;
        }

        cout<<"The Heap size is: "<<size()<<endl;
        cout<<"data in heap: ";
        for( int i = 1 ; i <= size() ; i ++ )
            cout<<data[i]<<" ";
        cout<<endl;
        cout<<endl;

        int n = size();
        int max_level = 0;
        int number_per_level = 1;
        while( n > 0 ) {
            max_level += 1;
            n -= number_per_level;
            number_per_level *= 2;
        }

        int max_level_number = int(pow(2, max_level-1));
        int cur_tree_max_level_number = max_level_number;
        int index = 1;
        for( int level = 0 ; level < max_level ; level ++ ){
            string line1 = string(max_level_number*3-1, ' ');

            int cur_level_number = min(count-int(pow(2,level))+1,int(pow(2,level)));
            bool isLeft = true;
            for( int index_cur_level = 0 ; index_cur_level < cur_level_number ; index ++ , index_cur_level ++ ){
                putNumberInLine( data[index] , line1 , index_cur_level , cur_tree_max_level_number*3-1 , isLeft );
                isLeft = !isLeft;
            }
            cout<<line1<<endl;

            if( level == max_level - 1 )
                break;

            string line2 = string(max_level_number*3-1, ' ');
            for( int index_cur_level = 0 ; index_cur_level < cur_level_number ; index_cur_level ++ )
                putBranchInLine( line2 , index_cur_level , cur_tree_max_level_number*3-1 );
            cout<<line2<<endl;

            cur_tree_max_level_number /= 2;
        }
    }

private:
    void putNumberInLine( int num, string &line, int index_cur_level, int cur_tree_width, bool isLeft){

        int sub_tree_width = (cur_tree_width - 1) / 2;
        int offset = index_cur_level * (cur_tree_width+1) + sub_tree_width;
        assert(offset + 1 < line.size());
        if( num >= 10 ) {
            line[offset + 0] = '0' + num / 10;
            line[offset + 1] = '0' + num % 10;
        }
        else{
            if( isLeft)
                line[offset + 0] = '0' + num;
            else
                line[offset + 1] = '0' + num;
        }
    }

    void putBranchInLine( string &line, int index_cur_level, int cur_tree_width){

        int sub_tree_width = (cur_tree_width - 1) / 2;
        int sub_sub_tree_width = (sub_tree_width - 1) / 2;
        int offset_left = index_cur_level * (cur_tree_width+1) + sub_sub_tree_width;
        assert( offset_left + 1 < line.size() );
        int offset_right = index_cur_level * (cur_tree_width+1) + sub_tree_width + 1 + sub_sub_tree_width;
        assert( offset_right < line.size() );

        line[offset_left + 1] = '/';
        line[offset_right + 0] = '\\';
    }
};


int main() {

    MaxHeap<int> maxheap = MaxHeap<int>(100);

    srand(time(NULL));
    for( int i = 0 ; i < 50 ; i ++ ){
        maxheap.insert( rand()%100 );
    }
    maxheap.testPrint();

    return 0;
}